A363085 - OEIS

A363085

Sum of the refactorable unitary divisors of n.

1, 3, 1, 1, 1, 3, 1, 9, 10, 3, 1, 13, 1, 3, 1, 1, 1, 30, 1, 1, 1, 3, 1, 33, 1, 3, 1, 1, 1, 3, 1, 1, 1, 3, 1, 46, 1, 3, 1, 49, 1, 3, 1, 1, 10, 3, 1, 1, 1, 3, 1, 1, 1, 3, 1, 65, 1, 3, 1, 73, 1, 3, 10, 1, 1, 3, 1, 1, 1, 3, 1, 90, 1, 3, 1, 1, 1, 3, 1, 81, 1, 3, 1, 97, 1, 3, 1, 97

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..88.

FORMULA

a(n) = Sum_{d|n, tau(d)|d, gcd(d,n/d)=1} d.

MATHEMATICA

a[n_] := DivisorSum[n, # &, CoprimeQ[#, n/#] && Divisible[#, DivisorSigma[0, #]] &]; Array[a, 100]

CROSSREFS

Cf. A034444, A336041, A363298.

Sequence in context: A114006 A050328 A191278 * A359577 A030401 A275888

Adjacent sequences: A363082 A363083 A363084 * A363086 A363087 A363088

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, May 27 2023

STATUS

approved